There is an increasing demand for high data rates in wireless networks, the use of wireless broadband having increased rapidly during the last decade and expected to grow even faster in the near future. To meet this demand, network operators must increase the capacity in their communication systems, which is a challenging task. The existing communication systems should preferably be evolved in a cost and time efficient manner so as to meet the requirements for higher data rates. In this respect, a number of approaches are possible. One option is to deploy more base stations and use smaller cells. However, with many small cells and dense deployment of base stations, interference between different cells will most likely increase. The large number of base stations further gives a high energy consumption entailing high costs and influencing the environment in a negative way. Further still, costs and delays associated with installation of base stations may be significant. The output power of the base stations should therefore be limited to highest possible extent.
From the above, it is clear that it is a challenging task to increase the capacity in the communication system in order to be able to provide the desired services to the users, while taking into account aspects such as requirements for energy efficiency, costs and interference. There is thus room for improvements in this regards within this field of technology.